Native Estimation Methods

There are times when we could all use a timely reminder that the collection of natural data is actually difficult and usually suspect. These two examples make it very clear.

My own education came about through a long exposure to the mining industry. Data costs money and its interpretation is always suspect. It is not uncommon for a mining project to be walked every year for decades with multiple odd ideas applied and tested. Thus when you visit a project you are shown a history of decades of failure.

Yet this is what magically makes mines. In the end, it takes a lot of good data painstakingly collected.

This has made me highly sensitive to the problems of collecting good data. That is why when claims are made regarding numbers, it is wise to review the methodology, not so much as to question anyone’s capability, but to get a measure of the probability of error.

In the case in hand, they had numbers telling them that changes were taking place. They went to local observers to get a second viewpoint that in both cases showed up serious experimental design error. A new better protocol evolves because of this.

You can put down fifty miles of boot work on a mineral property and see or uncover nothing, yet your prospector can walk you directly to a possible face of ore covered in moss. It still took both of you, because that fifty miles of nothing is also valuable data.

Dec 17, 2009

Native techniques prove better than science

Modern methods can answer a multitude of questions but sometimes traditional techniques are superior. Recent studies from the James Bay region of northern Canada and the Torres Strait islands off Australia show just how valuable local knowledge can be when it comes to the environment.

Colin Scott, an anthropologist from McGill University in Canada, has worked with two very different groups of indigenous people: the Cree of northern Quebec in Canada, and the Torres Strait Islanders, hunter-gatherers inhabiting a group of small islands off northern Australia. In each case he has documented the way in which the people interact with their environment and their detailed knowledge of the ecosystems around them.

Presenting at the BOREAS conference, a European Science Foundation project that took place at the Arctic Centre in Rovaniemi, Finland, Scott demonstrated how native knowledge can outshine modern scientific techniques when it comes to environmental monitoring.

In his first example Scott talked about the Torres Strait Islanders and their relationship with dugong, a large marine mammal, similar to the Caribbean manatee, which lives in the northern waters of Australia. The Islanders hunt these animals for their meat and fat. In recent years dugong numbers in their larger Indo-Pacific distribution are thought to have declined, mainly due to habitat degradation, fishing accidents and hunting; the International Union for Conservation of Nature lists the dugong as vulnerable to extinction.

While it is generally accepted that dugong populations in Australian waters are doing comparatively well, there is controversy about whether indigenous subsistence hunting is sustainable at current levels. However, monitoring the dugong population is far from easy. Scientists have been carrying out aerial surveys to count the mammals, but Islanders have argued that this method doesn’t provide an accurate picture.

The Islanders explained to Scott that dugong come onto shallower reefs on a high tide to graze sea-grass, but on a low tide they go into deeper water where they are very difficult to spot. During half the year, the highest tides are at night. What’s more, dugong are most comfortable coming onto the reef at night because they feel safer.

To keep an eye on trends in dugong numbers, the islanders use a variety of methods, including monitoring the pattern and quantity of sea-grass browsed in particular areas, and going out by boat to count the animals on fine, calm nights, informed as much by sound as by sight. “They told me that they can count, and they can differentiate between male and female dugongs, and between fat and skinny dugongs, by the sound of their breathing when they surface and blow,” Scott said.

Local practices that promote sustainable use of dugong include employing hunting areas on a rotational basis, and taking only animals that are in prime condition. What’s more, the Islanders avoid hunting when seas are rough, and on unfavourable tides and currents, so the pattern of hunting is always intermittent.

One Islander who witnessed biologists’ aerial surveys had accompanied them for the flight over reefs on daytime low tides. He commented that although reef surface features are more visible in such conditions, most dugong cannot be seen, because they have gone into deeper water. Only dugong in poor condition stay up on the reefs on a low tide, he elaborated, because they are too hungry to do otherwise. He was convinced, as are many Islanders, that aerial surveys significantly underestimate real dugong numbers.

Northern exposure

Over on the other side of the world, in northern Canada, aerial surveys have also been insufficient in themselves for monitoring population sizes. For many centuries the Cree, an indigenous group of people living in the James Bay region of northern Quebec (around 800km north of Montreal), have lived sustainably within their environment. They hunt a variety of animals including beaver, bear, moose, caribou and a variety of smaller game and fish. Cree hunters have a strong ethic that nothing should be wasted, so they kill just enough to feed themselves and provide some supplementary fur income. By rotating the territories over which they hunt, selectively hunting adult animals in prime condition, and adjusting the mix of the many food species upon which they rely, they ensure that the animal populations remain stable.

Until the mid-1980s the James Bay region, at the southern end of Hudson Bay in Canada, was inaccessible to most and the Cree were the only people who hunted in the area. However, in the mid-1980s, partly in response to pressure from sport-hunting and fishing groups, the Quebec provincial government granted public access to the region, via a previously locked road, known as the James Bay highway, which had been constructed for a major hydro-electric project in the early 1970s.

Sport hunters travelled from the more urbanized southern regions of the province, hoping to bag moose. “At the time, provincial wildlife managers were eager to open up access to this region, as they believed it would relieve the pressure on over-taxed hunting zones further south,” said Scott.

To check whether moose populations were stable the Quebec authorities relied on aerial surveys, every five or six years, to monitor numbers of the animals. In addition, there were annual records of the number of moose caught by sport hunters for each zone, which enabled some estimate of catch per hunting effort.

By the mid-1980s the Cree people in the southern portion of their traditional territory were already worried about the negative impact of forestry operations on moose populations and on their subsistence hunting. These worries were compounded with the influx of sport hunters, whose access had been enlarged thanks to forestry roads, and the opening of the James Bay highway. During the late 1980s Cree hunters became acutely concerned about moose numbers, particularly in ‘Zone 17’, a major provincial game management zone covering several thousand square kilometres in the southern part of the James Bay Cree region. Using their traditional system of monitoring moose populations - based on moose sightings, tracks, browse and faeces - the hunters were certain numbers had declined signficantly.

The Cree people alerted provincial wildlife managers, but for a time they were not taken seriously. Instead the authorities believed that the moose population must be stable because ‘catch per unit effort’ data based on rates of sport hunting success did not indicate a clear decline.

But by the early 1990s the authorities were forced to concede that there was a problem in zone 17, as it became clear that a crash in moose population was underway, with a decline of nearly 50% below 1985 levels by 1991, and a probable decline significantly greater than 50% compared to earlier decades when industrial forestry affected fewer Cree hunting territories.

“Opening the highway had opened up opportunities for the forestry sector as well, enabling them to clear cut the forest, and leaving the moose with less cover to hide in,” said Scott. The moose became easy targets and sport hunters became much more efficient. So their hunting success rates did not drop off for a few years, disguising the actual decline in the underlying moose population. As a result, authorities were lulled into a false sense of security.

Nowadays wildlife managers in Quebec have learned some lessons, and work more closely with the Cree, listening with greater credence to what they have to say, and with more respect for their intimate knowledge of the environment.

In both these instances the traditional methods of monitoring and managing ecosystems had significant advantages compared to modern techniques. Scott says that it is important that we continue to dismantle the divide between indigenous and scientific knowledge, and prioritize collaboration with indigenous populations. “Their methods often involve more checks, are sensitive to a broader range of variables, and have great potential to increase our understanding of complex ecological realities,” he said.